Duodenal bicarbonate secretion (DBS) is regulated by a luminal purinergic regulatory system comprised of the brush border intestinal alkaline phosphatase, nonlytic ATP release, and enterocyte P2Y receptors, which, when activated, augment epithelial DBS and likely function to regulate duodenal surface microclimate pH. Ham et al. investigated the role of luminal adenosine regulators and sensors including P1 receptors, adenosine deaminase, and nucleoside transporters in the regulation of DBS. This is the first study demonstrating that luminal adenosine stimulates DBS measured in vivo, adenosine-induced DBS is mediated by intestine by brush border A2B receptors and the cystic fibrosis transmembrane conductance regulator, and adenosine is endogenously generated in the duodenal lumen. These data complement the “adenosine scavenging” hypothesis wherein extracellular adenosine concentrations are regulated by apical nucleoside transporters and adenosine deaminase, which in turn regulate intestinal anion secretion and the microclimate pH.
See article at J Pharmacol Exp Ther 2010, 335:607–613.
- Copyright © 2010 by The American Society for Pharmacology and Experimental Therapeutics